This invention relates to improvements in an ignition coil device for the spark ignitor of an internal combustion engine.
A prior-art device of the specified type has been as shown in FIGS. 1 and 2. Referring to the figures, numeral 1 designates a coil assembly in which a primary coil and a secondary coil are wound in a manner to be insulated from each other and are covered with a molding material. A core 2 forms a magnetic path which is common to the primary coil and the secondary coil wound in the coil assembly 1. Numeral 3 indicates a terminal which is connected to one end of the primary coil, numeral 4 a terminal which is connected to the other end of the primary coil and one end of the secondary coil in common, and numeral 5 a high-voltage terminal which is connected to the other end of the secondary coil. The terminal 3, the terminal 4 and the high-voltage terminal 5 are respectively fastened integrally with the coil assembly 1 by a molding material.
FIG. 3 shows an equivalent circuit of the prior-art device. Here, symbol 1a denotes the primary coil, and symbol 1b the secondary coil. In addition, FIG. 4 is an electric circuit diagram showing the state of connection during the use of the prior-art device. Referring to FIG. 4, a battery 6 supplies current to the primary coil 1a of the ignition coil. An interrupter 7 interrupts the current through the primary coil 1a according to the ignition timing of the engine. An ignition plug 8 sparks upon receiving a high voltage which is generated across the secondary coil 1b of the ignition coil.
In operation, when the interrupter 7 interrupts the current flowing through the primary coil 1a at a predetermined time after the conduction thereof therethrough, the high voltage is induced in the secondary coil 1b and is supplied to the ignition plug 8 through the high-voltage terminal 5.
The prior-art ignition coil device is constructed and operated as described above. Therefore, when it is combined with another device such as a distributor having a rotary shaft, a housing for supporting the shaft, etc., it must be arranged so as to avoid the rotary shaft, the housing, etc. This has led to the disadvantage that the whole structure is not balanced and that space is wasted.